Refrigeration compressor



Dec. 23, 1952 cLow 2,622,788

REFRIGERATION COMPRESSOR Filed Jan. 19, 1946 2 SHEETS-SHEET l ZLQMIQ JDec. 23, 1952 A. RAMCLOW REFRIGERATION COMPRESSOR Filed Jan. 19, 1946 2SHEETS-SHEET 2 l I. 1 E N H I! Patented Dec. 23, 1 952 REFRIGERATIONCOMPRESSOR Axel Ramclow, Chicago, Ill., assignor to Mills Industries,Incorporated, Chicago, 111., a. corporation of Illinois ApplicationJanuary 19, 1946, Serial No. 642,348

8 Claims.

This invention relates to refrigeration compressors and is especiallyuseful in compressors of the direct-drive type, that is, of the type inwhich the crank shaft of the compressor is connected directly to, and isin effect a continuation of, the drive shaft of a motor forming a partof a unitary motor-compressor unit, although certain features of theinvention are not necessarily limited to this type of compressor.

It is the custom of the refrigeration industry to manufacturecompressors in sizes to meet the power output of the standard sizes ofelectric motors available on the market. It is also the custom of theindustry to produce condensing units having compressors of differentdisplacement volume for each size of driving motor. For example, achoice of three different compressor displacements may be provided for agiven size of motor and the selection will be determined'by therequirements of the refrigeration application for which the unit is tobe used. In one common type of compressor drive, in which the compressoris driven from the motor by mean of V-belts and sheaves, the desiredselection of three compressor displacements for each motor size isreadily obtained by the selection of sheaves having a pitch diameterratio which will provide the desired speed ratio between the motor andcompressor, it being understood that with this type of drive thecompressor is operated at a speed slower than that of the driving motor.

On the other hand, when direct-drive compressors, in which the motorrotor and the compressor have one common shaft, are employed, differentcompressor displacements have heretofore been possible only throughchanges of cylinder diameter and piston stroke. Such changes could bemade only by changing the fundamental dimensions of the compressor whichinvolved an entirely different model and size of compressor for eachcompressor displacement. This inflexibility had been a seriousdisadvantage of direct-drive compressors, although in certain otherrespects such compressors have definite advantages over the so-calledbelted type. Among such advantages is that the size of a direct-drivecompressor may be much less than that of the relatively slow speedbelt-drive compressors employing speed reduction means of the type abovedescribed. Compressor size is in inverse ratio to speed and therelatively high speed direct-drive compressors may, therefore, be verysmall. They may also be close coupled in relation to the motor, and thusvery compact, Lighter weight is also another advantageous character:istic.

One-of the objects of the present invention is to provide a direct-drivecompressor construction in which the compressor displacement may bechanged with substantially the same simplicity as is possible with therelatively slow speed belt drive type of compressor.

A further object of the certain aspects also useful in other,constructions;

Other objects and. advantages of the invention the followingdescription,-

will be apparent from taken in connection with the accompanyingdrawings, in which:

Fig. l is a cross-'sectional view of a two-cylinder opposd type ofrefrigeration compressor adapted-- to be driven directly from the shaftof an electric:

motor; and

Fig. 2 is a cross-sectional view of the come taken-at right angles tothe plane of Fig. 1 and showing in elevation the motor housing.

As shown, the crankcase ll of the compressor is cast integrally withopposed cylinder blocks l2 and with an arcuate flange is formed with ashoulder the edge of the housing or l3 at one end'which I4 adapted toreceive casing I5 of the drive motor, generally indicated by thereference by, means of a cylinder head '22 and cylinder head screws 23which extend through the head and into tapped holes inthe cylinder blockI2.

1 The clearance ofthe sleeve flange 18 within cylinder block l2 may besufficient to permit ready assembly and conformity of the flange to thecylinder shoulder l 'l, it having been found in practice that aclearance of five-thousandths to six-thousandths of an inch is adesirable cleari ance. The clearance of .the valve plate 2| within thecylinder wall is preferably less than the clearance of the sleeve.flange 18, a clearance of one-thousandths to three-thousandths of'aninchf having been found satisfactory inpractice. Thus thereispreferably a differential of, say," three-thousandths of .an inchbetween. the clearance of the sleeve flange and that of the valve plate.The relatively loose fit of the sleeve greatly facilitates manufactureand assembh'. The i8 is held tightly against the shoul invention istheiprofl vision of a lubricating system particularly well adapted tothis type of compressor, although from der I! by the valve plate 2| andcylinder head 22. and these parts may be assembled in gas-tight contactby lapping the contacting surfaces or by the use of suitable gasketstherebetween. They are held in permanent compression by means of thecylinder head screws 23.

A discharge valve assembly 24 is provided on the valve plate 2| and,being off-known construction, need not be described in detail. It may beconstructed in accordance with United States Patent No. 2,106,775, andprovides for discharge of compressed gas through an opening 25 in thevalve plate 2| into a chamber 28 in the cylinder head 22 in accordancewith conventional practice. The compressed gas is conducted from thechamber 26 through a discharge opening 27 to the condenser (not shown)in'the usual manner.

A piston 28 is positioned within the cylinder sleeve I 9 forreciprocating motion therein and is connected bymeans of a connectingrod 29 with an: eccentric 3| .mounted on a crank shaft 32 extendinglengthwise through the gas chamber 33 of the compressor. Anintake valve.34 is positioned on the head of the piston 28 which is o'f (hollowconstruction, said intake valve serving to admit refrigerant gas fromthe chamber 33 to a compression chamber 35in the sleeve l9 throughopenings .36 in the head 31 of the piston upon the .retractingstroke ofthepiston, said openings 36 .being closedby the valve 34 upon thecompressionstroke of the piston.

The shaft 32 is in effect a continuation of a drive shaft 38 of themotor 1.6 which passes through-an end plate 39 on the crankcase I I andis supported by .a bearing 4| integrally formed on the insideof said endplate 39'. Aremovable' sleevetype bronze journal 42, secured to theshaft 38, 32 provides bearing contact with .said bearing 41. Saidjournal 42 .is held in place against a shoulder 43 on the shaft 38 bymeans of a nut 44 positioned on the end of the shaft section-32and-affording.pressureagainst the two eccentrics 3| which are mounted onsaid shaft section. Adjacent the inner end of the shaft section 32 is athrust bearing 45 carried by a crankcase cover 46 which is secured tothe crankcase casting by means of screws 41. A steel ball 48 and thrustspring 49 are mounted within a hollow end'portion of the shaft 32, saidball engaging .the thrust bearing 45 and the spring serving to push theshaft 32, 38 toward the motor .to maintain contact of the elements :of ashaft seal provided at the point of entrance of the shaft section 38into the crankcase. Said seal may be of any suitable or desiredconstruction, as, for example, the construction :shown in Patent No.2,245,106.

A body'of oil 52 is contained within the lower part of the crankcase Hand an oil reservoir 53 is provided between the'bearing 4| and aboss 54on the wall 39 of thecrankcasecasting .l i through which the-shaft38.extends-. Acoil spring belt .55 is mounted upon the journal 42 and anidler sheave 56 rotatably mounted on a screw 5'! extending into a boss58 provided on the .inside of the wall 39 below the level of the oil inthe crankcase. Said belt is held in place by means of a groove59 in thejournal 42 and a groove 5| in the sheave 56. It is located within achannelshaped baflle 62 and above the inner end of the journal 42 within:said channel shaped baffle, a curved bafile '63 is .provided.

Said coil spring belt 55 is under such tension as .to' separate thecoils slightly and said coils are ad'apted'to open up somewhat more asthey pass 'isters with an oil hole 72 in one cylinder sleeves on thearound the bottom of the sheave 56 and the top of the grooved journal42. Capillary attraction causes lubricating oil to enter the interior ofthe spring and to be held between the coils as the belt travels upwardlyfrom the body of oil 52. As it passes around the top of the journal 42,centrifugal force acting on the oil exceeds the capillary attraction andthe adhesion tending to retain the oil within the coils, and this,coupled with the opening up of the coils, causes the oil to leave thebelt and to be thrown against the curved bathe-63 which deflects it intothe reservoir 53. The latter is thus kept filled with oil and theexposed parts of the seal 5| are submerged "within'the body of oil inthis reservoir. The journal 42 has a helical oil groove 64 in theperiphery thereof which communicates with a radialpil hole extendingthrough the journal from an annular groove 66 formed on the exteriorthereof. The shaft 38 has an annular groove 61 adapted to receive oilpassing through the hole '65, and said shaft 38 is provided with an oilhole 68 opening into an o-ilpassage 69 drilled longitudinally in theshaft 38, 32. Said passage extends to the hollow portion of the shaftsection 32 in which the spring 49 and ball 43 are located. An oil holell extends from thejpassage 69 radially through the shaft section 32 andregof the eccentrics 3'! from which the oil passes into a semicirculargroove 13 in the large end of the connecting rod 29 which is nearest themotor. An oil hole 14 in the shaft section 32 registering with an .oilhole "#5 in the other eccentric supplies oil to a semicircular groove l5in the other connecting rod.

From 'said semicircular grooves in the large ends 'of 'the connectingrods an oil passage 1! leads to an oil groove if! in the wrist pin 19 bywhich the connecting rod is connected to the piston 28.

The connecting rods 29 are assembled on the eccentrics 3! in such mannerthat the direction of rotation will force oil in the connecting rod oilgrooves 13 and 76 through the passages 11 to the pistonpin oil grooves78. Theadhesion of the oil to the eccentrics during the rotation of the"latter builds up in the oil grooves 13 and 16 an accumulated pressurewhich forces the oil through the passages 17 to the wristpin grooves 18.

The refrigerant vapor to'be compressed enters the crank case through aconventional valve 8| and an opening 82, and, as previously indicated,is drawn into the compression chamber 35 in the suction stroke of thepistons. After compression it passes through the discharge valve 24 andoutlet opening 21.

In order to provide a different compressor .dis placement when requiredfor a particular use of the compressor, the cylinder sleeves i9 may bereadily removed and replaced with sleeves .having a bore of differentdiameter. The construction above described makes it possible to makethis substitution easily while at the same time providing the gas-tightrelationship of the parts which is essential in compressor construction.

For the purpose of determining the extent of the effective stroke of thepiston, openings 83 may, if desired, be provided in the walls of thecylinder sleeves is, the location of these openings or slots obviouslydetermining the length of the effective stroke. Thus the compressordisplacement may be varied by substitution of sleeves having theopenings 83 differently located I lengthwise thereof as well as by thesubstitution of sleeves of different bore diameter.

The operation of the compressor does not differ substantially from thatof other known constructions, with'the exception of the lubricationsystem which has heretofore been described, but the new construction hasmany advantages from the standpointof manufacturing and servicing whichprevious constructions do not have.

' The use of the replaceable cylinder sleeves H which may have variousbores and be fitted with corresponding pistons, permits the use of asingle model of cylinder block casting to produce compressors havingvarious displacements. This is a great advantage in direct-drivecompressors wherein the displacement cannot be changed by changing thecompressor speed as can be done with belt-driven compressors. The use ofthe present invention thus makes it unnecessary to have a greater numberof cylinder block models for direct-drive compressors than would benecessary in a comparable line of belt-driven compressors. I

In the conventional refrigeration compressor, in which the cylinder iscast integrally with the crankcase and is machined to provide thesurfaces necessary to cooperate with the piston (without the use of aseparate cylinder-sleeve), the machining of the cylinder bore is a verydimcult and exacting job. The accuracy of the cylinder bore dimensionmust be held within tolerance limits of a few ten-thousandths of an inchin relation to the piston, and if any error is made in the machining ofeither of the cylinders in the casting, the entire casting must bediscarded or the eiiciency of the compressor will be impaired. It ismuch quicker and. less critical to machine a cylinder sleeve andcylinder block separately than it is to machine the two units combinedin one casting and, furthermore, the cylinder block does not have to bemachined nearly so accurately to properly receive the sleeve as if thepiston were to work directly in a cylindervbore formed in the casting.With the construction of my invention only a relatively short portion ofthe cylinder block need be machined and the short machined surfaceswhich are contacted by the cylinder sleeve may have a relativelygenerous dimensional tolerance as compared with the tolerance betweenthe piston and the surface against which it operates.

The separate cylinder sleeves can be machined in automatic screwmachines with every operation complete except the final finish of thebore which can bedone quicker and more accurately in individual cylindersleeves than it could be in a complicated cylinder block.

For the above and other reasons, a great deal of time and expense issaved in the manufacture of compressors constructed in accordance withthe present invention and less skill is required than in the manufactureof conventional compressors.

Another advantage of the present invention lies in the elimination ofcylinder wall distortion which is sometimes caused in conventionalcompressor construction by radial thrust of cylinder head screws whenthey are tightened into the cylinder block. These screws are ordinarilylocated in a circle around the cylinder bore in the casting and thethrust is at times sufficient to cause deflection of the cylinder walltoward the center of the cylinder. This deflection may be of sumcientamplitude to exceed the amount by which the piston is smaller than thecylinder bore and it may cause sticking of the piston for tion, thediameter of the valve plate is greater than the diameter of the annularflange on the sleeve and therefore the radial thrust would be on thevalve plate and not on the sleeve, Furthermore, any distortion permittedby the valve plate would be taken up by the internal shoulder in thecylinder block, the internal diameter of which exceeds the outsidediameter of the cylinder sleeve by an amount greater than any likelydeflection of the shoulder.

A further advantage of the present construction is that the assembly ofthe mechanism is much simpler and a more compact unit can be obtainedthan with prior construction. This is by reason of the fact that asub-assembly of the piston, connecting rod, eccentric and certain otherparts may be made within the crankcase before the cylinder sleeve isinserted, which could not be done if integral cylinders were employedsince the assembly referred to would be too long'to lit-between theinner ends of opposed cylinders. There are also other assemblyadvantages which will be apparent to those familiar with the manufactureof apparatus of this character.

It will also be apparent that with the present construction the cylindersleeves (and pistons, if necessary) may be readily and quickly replacedby a serviceman in the field or in a local shop.

The lubricating mechanism hereinabove described is particularly usefulin a direct-drive type of compressor for the purpose of lubricating themotor shaft and seal elements, as well as providing effective piston pinlubrication, and, as has been pointed out, the cylinder sleeveconstruction of the present invention has especial advantages in suchcompressors since the displacement volume thereof cannot be changed bymerely changing the compressor speed as in the case of beltdrivencompressors.

The foregoing detailed description has been given for clearness ofunderstanding only, and nounnecessary limitations should be understoodtherefrom, but the appended claims should be construed as broadly aspermissible in view of the prior art.

I claim:

V l. A refrigeration compressor comprising a crankcase having a cylinderblock formed therein, the latter having an internal annular shoulderformed therein, a separate cylinder sleeve positi'o'ned'entirely withinsaid cylinder block and extending into the crankcase, said sleeve havingan external annular flange engaging said shoulder, a valve plate ofgreater diameter than said flange engaging said flange and having itsperiphery in contact with the interior of the cylinder block, a cylinderhead contacting said plate, cylinder head screws holding said parts inassembled relation against said shoulder under compression, a pistonreciprocably mountedin said cylinder sleeve, and means for actuatingsaid position. Y 2. A refrigeration compressor comprising a crankcasehaving opposed cylinder blocks formed therein, the latter each having aninternal annular shoulder formed therein, a separate cylinder sleevepositioned entirely within said cylinder sleeve positioned entirelywithin said cylinder block and. extending into the crankcase, saidsleeve having an external annular flange engaging said shoulder, a valveplate of greater diameter than said flange engaging saidfiange andhaving its peripheryincontact with the interior of the cylinder block, acylinder head contacting said plate, cylinder head screws holding saidparts inassembled relationiagainst said shoulder under compression, apiston reciprocably mounted in said cylinder sleeve, and means foractuating said piston.

3. A refrigeration compressor comprising a crankcase having a cylinderblock formed therein, 'the latter having an internal annular shoulderformed therein, a separate cylinder sleeve positioned entirely withinsaid cylinder block and extending into the crankcase, said sleeve.havingan external annular flangeengaging said shoulder, a valve plateof greater diameter than said flange engaging said flange and havingitsperiphery in contact with the interior of the cylinder block, a cylinderhead contacting said plate, cylinder head screws holding said parts.inassembled relation against said shoulder under compression, a pistonreciprocably mounted in said cylinder sleeve, and means for actuatingsaid piston, said means including a compressor shaft and a motordirectly connected with said sha'ftfcr driving the same.

4. A refrigeration compressor comprising a crankcase having a cylinderblock formed therein, the latter having an internal annular shoulderformed therein, a separate cylinder sleeve positioned entirely Withinsaid cylinder block and extending into the crankcase, said sleeve havingan. external annular flange engaging said shoulder, the clearancebetween said sleeve and the walls of the cylinder block beingsufflciently great to permit ready manual assembly of the sleeve in theblock, a valve plate of greater diameter than said flange engaging saidflange and having its periphery in contact with the interior of thecylinder block, a cylinder head contacting said plate, cylinder headscrews holding said parts in assembled relation against said shoulderunder compression, a piston reciprocably mounted in said cylindersleeve, and means for actuating said piston.

5. A refrigeration compressor comprising a crankcase having a cylinderblock formed therein, the latter having an internal annular shoulderformed therein, a separate cylinder sleeve positioned entirely withinsaid cylinder block and extending into the crankcase, saidsleeve havingan external annular flange engaging said shoulder, a valve plate.engaging said flange and having its periphery in contact with theinterior of the cylinder block, the clearance between the .sleeve andthe walls of the cylinder block being substantially greater than thatbetween the valve plate-and the Walls of said cylinder block acylinderhead contacting said plate, cylinder head screws holding said parts .inassembled relation against said shoulder under compression, a pistonreciprocably mounted in said cylinder sleeve, and means for actuatingsaid piston.

:6. A refrigeration compressor comprising a crankcase having a cylinderblock formed therein, the latter having an internal annular shoulderformed therein, a separate cylinder sleevepositioned entirely withinsaid cylinder block and extending .into the crankcase, said sleevehaving anexternal annular flange engaging said shoulder, a valve plateof greater diameter than said flange engaging said flange and having itsperiphcry in contact with the interior of the cylinder block, a cylinderhead contacting said plate, cylinder head screws holding said parts inassembled relation against said shoulder under compression, a pistonreciprocably mounted in said cylinder sleeve, and means for'actuatingsaid piston, said cylinder sleeve being slotted intermediate its ends todetermine the length of the effective stroke of said piston.

7. In a compressor of the class described, the combination of a-cylinderblock, a cylinder sleeve, a circular valve plate, a cylinder head andcylinder head screws, said cylinder block having an internal'annularshoulder and said cylinder sleeve having an externalannular flangenesting in said cylinder block in contact with said internal anularcylinder block shoulder, said circular valve plate'being of greaterdiameter thansaidflange and being positioned within said cylinder blockin contact with the external annular flange of said cylinder sleeve,said cylinder head being in pressure-exerting relationship with saidvalve plate, and said cylinder head screws being secured into saidcylinder block under tension holding said cylinder head in place, saidvalve plate and said external flange of said cylinder sleeve being infixed series relationship against said internal annular shoulder of saidcylinder block and being disposed inside said block in close-fittingrelationship with the wall thereof.

8. In a compressor of the class described, the combination of acylinderblock, a cylinder sleeve, a circular valve plate, a cylinderheadand cylinder head screws, said cylinder block having an internal annularshoulder and said cylinder sleeve having an external annular flangenesting in said cylinder block in contact with said internal annularcylinder block shoulder, said. circular valve plate being positionedwithin said cylinder block in contact with the external annular flangeof said cylinder sleeve, said cylinder head being in pressure-exertingrelationship with said valve plate, and said cylinder head screws beingsecured into said cylinder block under tensionholding said cylidner headin place, said valve plate and said external flange of said cylindersleeve being in fixed-series relationship against said internal annularshoulder of said cylinder block and being disposed inside said block inclose-fitting .relationship with the wall thereof, said circular valveplate being of greater diameter than the maximum diameter of saidsleeve.

AXEL .RAMCLQW.

.REFERENCES CITED The following references are'of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 221,223 Epping -1 Nov. 4,18791,295,529 Lawhead Feb. 25,1919 1,583,535 Dubrovin May 4, 1926 1,643,645Strand Sept. 27, 1927 1,763,395 Frederick June 10, 1930 1,915,165Ramclau June'20, 1933 1,955,958 Greenwald Apr. 24, 1934 2,106,775 TraskFeb. '1, 1938 2,245,106 Karlberg June 10, 1941 2,406,229 Leinweber Aug.20,1946 2,436,854 Corey Mar. 2, 1948

